Name: structure-function studies in mouse embryonic stem cells using recombinase-mediated cassette exchange
Uploaded: 2017-04-27T15:00:00
Description: Watch this Scientific Journal Video about Structure-function Studies in Mouse Embryonic Stem Cells Using Recombinase-mediated Cassette Exchange at JoVE.com

Vi takker Jinke D&#39;Hont, Frederique van Rockeghem, Natalie Farla, Kelly Lemeire, og Riet De Rycke for deres fremragende tekniske support. Vi takker også Eef Parthoens, Evelien Van Hamme, og Amanda Goncalves fra Bioimaging Core Facility for Inflammation Forskningscenter for deres eksperthjælp. Vi anerkender medlemmer af vores forskningsgruppe for værdifulde diskussioner. Dette arbejde blev støttet af den belgiske Science Policy (Belspo universitetscenter Type polakker - Award IAP VII-07 DevRepair; https://devrepair.be), af Dronning Elisabeth Medical Foundation, Belgien (GSKE 2008-2010; http: // www .fmre-gske.be), og af de samordnede Research aktioner (GOA 01G01908) af Ghent Universitet, Belgien (http://www.ugent.be/en/ghentuniv). SG er en post.doc af Flandern forskningsmidler (FWO-V).

Alle forsøg på mus blev udført i henhold til de institutionelle, nationale og europæiske dyr regler. 1. Isolering af RMCE-kompatible KO mESCs <ol><li> Avle heterozygote KO-mus med RMCE-kompatible mus, såsom ROSALUC mus 10 eller ROSA26-iPSC mus 21. Begge RMCE-kompatible mus blev holdt på en blandet 129 / C57BL6 / Swiss baggrund. BEMÆRK: Passage med heterozygote KO mus tilrådes at overvinde embryonal letalitet i homozygote KO mus. </li><li> Anvende P...

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Vores Mesc isolation metode er brugervenlig og kræver ikke avancerede færdigheder eller udstyr, såsom mikrokirurgi af blastocyster. Således er denne teknologi er tilgængelig for en stor del af det videnskabelige samfund. Enhver med grundlæggende cellekultur erfaring kan forplante ICM udvækster og etablere mESCs linjer. Men skylningen og håndtering af blastocyster kræver nogle praksis. En mundpipette bruges til at overføre blastocyster og består af en mikropipette, en mikropipette holder, slanger og en aspirat...

Det anslås, at pattedyrgenomer indeholder omkring 20.000 proteinkodende gener. Alternativ splejsning og posttranslationelle modifikationer yderligere øge protein repertoire. Proteiner har en modulær struktur 1 og ofte indeholde multiple interaktionsdomæner, som tillader deres rekruttering til forskellige protein-komplekser og deres deltagelse i flere cellulære processer 2. Et eksempel er det multifunktionelle protein kaldet p120ctn. p120ctn kodes af Ctnnd1 genet og består af et stort centralt bæltedyr gentagelsesdomæne flankeret af en N-terminal og en C-terminal region. Bæltedyret domæne p120ctn binder til en særdeles konserveret juxtamembrandomæne af klassiske cadheriner, som er involveret i celle-celle-adhæsion, men det binder også til den transskriptionsrepressor Kaiso. Det N-terminale domæne af p120ctn interagerer med forskellige kinaser, phosphataser, små RhoGTPases og mikrotubulus-associeret proteins 3. Interessant, som et resultat af alternativ splejsning, p120ctn isoformer kan genereres fra fire alternative startkodoner 4. p120ctn isoform 1A er den længste, da det er oversat fra den mest-5&#39; startkodon og indeholder fuldlængde N-terminale segment. I p120ctn isoformerne 3 og 4 er dette N-terminale segment delvist og fuldstændigt henholdsvis slettet. Forstå den præcise rolle proteiner (eller protein-isoformer) og deres domæner i forskellige cellulære funktioner fortsat en udfordring. Genmålretning i mESCs muliggør studiet af funktionen af ​​et protein gennem genetisk deletion af det tilsvarende gen og har bredt bidraget til identifikation af udviklingsmæssigt vigtige og sygdomsrelaterede relevante gener og veje. Dette gennembrud i revers genetik var resultatet af fremskridt inden for Mesc isolation og genmålretning grund homolog rekombination 5 </sop&gt;. Homolog rekombination er en proces, hvor DNA-fragmenter udveksles mellem to lignende eller identiske nucleinsyre-dele efter dobbeltstrenget (ds) DNA-brud. Normalt HR er ineffektivt, fordi dsDNA pauser er sjældne. Nylig kunne effektiviteten af homologi-dirigeret genmålretning øges ved anvendelse af stedspecifikke nukleaser 6, 7, men desværre disse er tilbøjelige til off-target effekter 8. En mere pålidelig teknik til at muliggøre genmålretning er RMCE, som er baseret på stedspecifikke rekombinationssteder systemer såsom Cre / loxP eller FLPe / Frt. LoxP og Frt sekvens findes i bakteriofag P1 og Saccharomyces cerevisiae henholdsvis og består af 34 bp, herunder en asymmetrisk 8 bp sekvens, der bestemmer orienteringen af sitet. På den anden side, orienteringen af ​​for eksempel to loxP-sites inden for en DNA-strækning vil afgøre, om floxed DNA bliver udskåret eller inversed upon Cre-medieret rekombination 9. Desuden kan Cre også inducere en translokation hvis to steder er placeret på forskellige kromosomer. RMCE drager fordel af Heterospecifikke rekombinationssteder, der ikke krydsreagerer, og som er indlejret i et genomisk locus. I nærvær af et donorplasmid, der indeholder et DNA-fragment flankeret af de samme Heterospecifikke sites, vil rekombinasen indsætte dette DNA-fragment i RMCE-kompatible genomiske locus på grund af dobbeltstrenget samtidig translokation (figur 1). Her, kan kun korrekt RMCE-målrettede kloner gøre lægemiddelresistens takket være en promotor på den indkommende vektor, som genskaber en &quot;fanget,&quot; promotor-mindre neomycinresistensgen (NeoR) til stede i R26-genomet af docking-celler (figur 1) 10, 11. Dette resulterer i en meget høj målretning effektivitet, ofte tæt på 100% 11, &lt;/ sup&gt; 12. Afslutningsvis RMCE målretning er yderst effektiv og kan anvendes til struktur-funktioner undersøgelser; men det kræver en præfabrikerede genomiske locus. <img alt="figur 1" src="/files/ftp_upload/55575/55575fig1.jpg" /> Figur 1. Skematisk repræsentation af RMCE-medieret Målretning. RMCE giver mulighed for udveksling af DNA-segmenter fra et indkommende vektor målretning til en defineret genomisk locus hvis begge harbor to Heterospecifikke FRT-steder (skildret af hvide og røde trekanter). Derudover den konstruerede genomiske locus indeholder et promotorløst og trunkeret neomycin-resistens (NeoR) gen. Ved at tilvejebringe en promotor og startkodon i den indkommende DNA-fragment, kun korrekte rekombinationsbegivenheder genoprette neomycinresistens, hvilket resulterer i effektiviteter høje målretning. <a href="http://ecsource.jove.com/files/ftp_upload/55575/55575fig1large.jpg" target="_blank">Klik her for at se en større version af t</a>hans figur. Genommanipulation i mESCs muliggør frembringelsen af ​​RMCE-kompatibel mus. I 1981, to grupper formået at tage pluripotente celler fra den indre cellemasse (ICM) af blastocyster og opretholdelse dem i kultur 13, 14. mESCs er i stand til selvfornyelse og differentiering i alle typer af embryonale og voksne celler, herunder kim-celle afstamning. Derfor genmålretning i mESCs muliggør omvendt genetiske undersøgelser gennem udvikling af konstitutive eller betingede (ved hjælp af Cre / LoxP-system) KO-mus. Men den klassiske måde at isolere mus ES-celler er meget ineffektiv. Flere store forbedringer har stærkt forøget succesraten for afledt Mesc linjer, herunder anvendelse af et defineret serum-udskiftning (SR) medium 15, vekslende mellem Mesc medium indeholdende SR og føtalt bovint serum (FBS) 16, og anvendelsen af farmakologiske forbindelser, såsom pluripotin eller 2i 17. Pluripotin, en lille syntetisk molekyle, giver mulighed for opformering af mESCs i en udifferentieret tilstand i fravær af leukæmiinhiberende faktor (LIF) og muse embryonale fibroblaster (MEF) 18. Endelig er det blevet vist, at mESCs kan isoleres med en meget høj effektivitet (næsten 100%), når en SR / FBS medium alternerende protokol er kombineret med LIF og pluripotin 19, 20. Disse protokoller muliggør effektiv isolering af RMCE-kompatibel KO mESCs, der efterfølgende kan anvendes til struktur-funktions-undersøgelser. Dette papir beskriver en fremgangsmåde, der gør det muligt at identificere de vigtigste domæner eller rester i et protein, der er ansvarlige for specifikke cellulære processer. Til dette formål en pipeline af avancerede teknologier, der muliggør effektiv Mesc isolation, målrettede vektor samling, og Mesc målretning var skabed. Som sådan, store paneler med proteinisoformer, domæne mutanter og nedstrømseffektorer kan indføres i KO mESCs og kan evalueres for deres evne til at redde in vitro KO fænotype.

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	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">ROSALUC Mice</td>
			<td style="width:143px;">made in house</td>
			<td style="width:107px;"></td>
			<td style="width:245px;">frozen sperm available upon request</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">R26-iPSC mice</td>
			<td style="width:143px;">made in house</td>
			<td style="width:107px;"></td>
			<td style="width:245px;">frozen sperm available upon request</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Vessel probe</td>
			<td style="width:143px;">Fine Science Tools</td>
			<td>10160-13</td>
			<td style="width:245px;">to check for copulation plugs</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">M2 medium</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:107px;">M7167</td>
			<td style="width:245px;">make aliquots and store at -20&#176;C</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Fine forceps (Dumont #5 Standard tip Student forceps)</td>
			<td style="width:143px;">Fine Science Tools</td>
			<td style="width:107px;">11251-10</td>
			<td style="width:245px;">spray with 70% EtOH before use (do not autoclave)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">23G needles</td>
			<td style="width:143px;">Fine-ject</td>
			<td style="width:107px;">8697</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">1-ml syringes</td>
			<td style="width:143px;">Soft-ject</td>
			<td style="width:107px;">6680</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">60-mm bacterial grade plates (for flushing)&#160;</td>
			<td style="width:143px;">Gosselin</td>
			<td style="width:107px;">BB60-01</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Mouth pipette</td>
			<td style="width:143px;">made in house</td>
			<td style="width:107px;"></td>
			<td style="width:245px;">see discussion</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Mouse embryonic fibroblasts (MEFs, TgN (DR4)1 Jae strain)</td>
			<td style="width:143px;">ATTC</td>
			<td style="width:107px;">SCRC-1045</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">TgN (DR4)1 Jae mice</td>
			<td style="width:143px;">The Jackson Laboratory</td>
			<td style="width:107px;">3208</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Mitomycin C&#160;</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:107px;">M0503</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Phosphate buffered saline (PBS) without calcium or magnesium</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">14190-094</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:272px;">Tg(DR4)1Jae/J mice</td>
			<td style="width:143px;">JAX</td>
			<td style="width:107px;">3208</td>
			<td style="width:245px;">mice that contain four drug-selectable genes and DR4 MEFS confers resistance to neomycin, puromycin, hygromycin and 6-thioguanine</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">0.1% Gelatin</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:107px;">G1393</td>
			<td style="width:245px;">Dissolve 0.5 g in 500 ml distilled water, autoclave and store at 4&#176;C.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Trypsin (0.25%)&#160;</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">25200-056</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">2 &#956;M pluripotin</td>
			<td style="width:143px;">Cayman Chemical</td>
			<td style="width:107px;">10009557</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:272px;">pRMCE-DV1</td>
			<td style="width:143px;">BCCM/LMBP collection&#160;</td>
			<td style="width:107px;">LMBP 08870</td>
			<td style="width:245px;">public available from the BCCM/LMBP collection (http://bccm.belspo.be)&#160;</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:272px;">cre-excised pRMCE-DV1</td>
			<td style="width:143px;">BCCM/LMBP collection&#160;</td>
			<td style="width:107px;">LMBP 08195</td>
			<td style="width:245px;">public available from the BCCM/LMBP collection (http://bccm.belspo.be)&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">pCAG-FlpE-IRES-Puro-pA&#160;</td>
			<td style="width:143px;">Addgene</td>
			<td style="width:107px;">20733</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">heat-shock competent DH5&#945; bacteria&#160;</td>
			<td style="width:143px;">made in house</td>
			<td style="width:107px;"></td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Gateway pDONR221 vector</td>
			<td style="width:143px;">Thermo Fisher</td>
			<td style="width:107px;">12536-017</td>
			<td style="width:245px;">contains kanamycin-resistance gene</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">BP clonase II mix</td>
			<td style="width:143px;">Thermo Fisher</td>
			<td style="width:107px;">11789-020</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">LR clonase II mix</td>
			<td style="width:143px;">Thermo Fisher</td>
			<td style="width:107px;">11791-020&#160;</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Luria Broth (LB)&#160;</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Ampicillin&#160;</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Applied Biosystems 3730XL DNA Analyzer</td>
			<td style="width:143px;">Thermo Fisher</td>
			<td style="width:107px;">3730XL</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">G418</td>
			<td style="width:143px;">Thermo Fisher</td>
			<td style="width:107px;">11811-023</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Lipofectamine 2000 transfection reagent</td>
			<td style="width:143px;">Thermo Fisher</td>
			<td style="width:107px;">11668027</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Lipofectamine LTX transfection reagent</td>
			<td style="width:143px;">Thermo Fisher</td>
			<td style="width:107px;">15338100</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Effectene transfection reagent</td>
			<td style="width:143px;">Qiagen</td>
			<td style="width:107px;">301425</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">GATEWAY pENTR 1A vector</td>
			<td style="width:143px;">Thermo Fisher</td>
			<td style="width:107px;">A10462</td>
			<td>recombination-compatible vector</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">mouse monoclonal anti-p120ctn antibody</td>
			<td style="width:143px;">BD Transduction Laboratories</td>
			<td style="width:107px;">610134</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">mouse monoclonal anti-Ecadherin antibody</td>
			<td style="width:143px;">BD Transduction Laboratories</td>
			<td style="width:107px;">610181</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">General equipment:</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Sterile dissection tools</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td style="width:245px;">fine scissors and forceps for dissecting the uterus</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Sterile pipettes: 5 ml, 10 ml and 25 ml</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">15-ml and 50-ml conical centrifuge tubes</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:272px;">96-well culture plates V-shaped bottom and flat bottom)&#160;</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Culture dishes: 24 wells, 12 wells and 6 wells</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Multichannel pipettes (to pipette 30, 50, 100 and 200 &#956;l)&#160;</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Sterile multichannel reservoirs</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Access to a laminar air flow</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:272px;">Access to an incubator at 37&#176;C with 5% CO2</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Access to an inverted microscope</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Access to a bench-top centrifuge</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Access to a stereo microscope with transmitted-light&#160;</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Culture media:</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">MEF Medium:</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td style="width:245px;">stored at 4&#176;C; warm 30 min at 37&#176;C before use</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">&#160;Dulbecco&#8217;s modified Eagle&#8217;s medium (DMEM)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">41965-062</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">10% fetal bovine serum (FBS)</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:107px;">F-7524</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">L-glutamine (2 mM)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">25030-024&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Sodium pyruvate&#160; (0.4 mM)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">11360-039&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">penicillin (100 U/ml)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">15140-122&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">streptomycin (100 &#181;g/ml)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">15140-122&#160;</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">SR-based mESC medium:</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td style="width:245px;">stored at 4&#176;C; warm 30 min at 37&#176;C before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">DMEM/F12</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">31330-038</td>
			<td style="width:245px;">mixed in a 1:1 ratio</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">15% knock-out serum replacement (SR )</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">10828&#8211;028</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">L-glutamine (2 mM)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">25030-024&#160;</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">0.1 mM non-essential amino acids&#160;</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">11140-050</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">penicillin (100 U/ml)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">15140-122&#160;</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">streptomycin (100 &#181;g/ml)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">15140-122&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">&#946;-mercaptoethanol (0.1 mM)&#160;</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:107px;">M 3148&#160;</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">2,000 U/ml recombinant mouse LIF&#160;</td>
			<td style="width:143px;">(IRC/VIB Protein Service facility)</td>
			<td style="width:107px;"></td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">FBS-based mESC medium (similar to SR-based mESC medium):</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td style="width:245px;">stored at 4&#176;C; warm 30 min at 37&#176;C before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">Knockout DMEM</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">10829-018&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">15% FBS</td>
			<td style="width:143px;">Hyclone</td>
			<td style="width:107px;">SH30070.03E</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Differention Medium</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td style="width:245px;">stored at 4&#176;C; warm 30 min at 37&#176;C before use</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:272px;">Iscove&#39;s Modified Dulbecco&#39;s Medium (IMDM)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">21980-032&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">15% FBS</td>
			<td style="width:143px;">Hyclone</td>
			<td style="width:107px;">SH30070.03E</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">5% CD Hybridoma Medium(1x) liquid&#160;&#160;</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">11279-023&#160;</td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">&#160;2 mM L-glutamine</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">25030-024&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">0.4 mM 1-thioglycerol</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:107px;">M-6145</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">50 &#956;g/ml ascorbic acid</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:107px;">A-4544&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">penicillin (100 U/ml)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">15140-122&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">streptomycin (100 &#181;g/ml)</td>
			<td style="width:143px;">Gibco</td>
			<td style="width:107px;">15140-122&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2i</td>
			<td style="width:143px;"></td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">1 &#956;M Erk inhibitor PD0325901&#160;</td>
			<td style="width:143px;">Axon Medchem</td>
			<td style="width:107px;">Axon 1408</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:272px;">3 &#956;M Gsk3 inhibitor CHIR99021</td>
			<td style="width:143px;">Axon Medchem</td>
			<td style="width:107px;">Axon 1386</td>
			<td></td>
		</tr>
	</tbody>
</table>

structure-function studies in mouse embryonic stem cells using recombinase-mediated cassette exchange

Genmanipulation i muse embryoer eller embryonale stamceller (mESCs) giver mulighed for undersøgelse af funktionen af ​​et givet protein. Proteiner er arbejdsheste cellen og ofte bestå af flere funktionelle domæner, som kan påvirkes af posttranslationelle modifikationer. Udtømningen af ​​hele proteinet i betinget eller konstitutiv knock-out (KO) mus tager ikke højde for denne funktionel diversitet og regulering. En Mesc linje og en afledt musemodel, hvori en docking site for FLPe rekombinationsmedieret kassette udveksling (RMCE) blev indsat i ROSA26 (R26) locus, er tidligere blevet rapporteret. Her rapporterer vi på en struktur-funktion tilgang, der muliggør molekylær dissektion af de forskellige funktioner i en multidomæneproteinet protein. Med henblik herpå skal RMCE-kompatibel mus krydses med KO mus og derefter RMCE-kompatible KO mESCs skal isoleres. Dernæst kan et panel af formodede rednings konstrukter indføres i R26 locus via RMCE targeting. Kandidatforbindelserne rednings cDNA&#39;er kan nemt indsættes mellem RMCE sites af målvektoren ved hjælp rekombination kloning. Dernæst KO mESCs transficeret med målvektoren i kombination med et FLPe rekombinase ekspressionsplasmid. RMCE reaktiverer promotorløse neomycinresistensgen i ROSA26 docking sites og tillader selektion af den korrekte targeting event. På denne måde opnås høj målretning effektivitet tæt på 100%, hvilket muliggør indsættelse af flere formodede rednings konstruktioner i en semi-high throughput måde. Endelig kan et væld af R26-drevne rednings-konstruktioner testes for deres evne til at redde fænotype, der blev observeret i forældrenes KO mESCs. Vi præsenterer en proof-of-principle struktur-funktion undersøgelse i p120 catenin (p120ctn) KO mESCs anvender endoderm differentiering i embryoide legemer (EBS) som den fænotypiske udlæsning. Derigennem kan identifikation af vigtige domæner, formodede nedstrømsstier, og sygdomsfri relevante punktmutationer, der ligger til grund for KO fænotyper for et givet protein.

Fremgangsmåden til isolering RMCE-kompatibel KO Mesc linjer er afbildet i figur 2. To på hinanden følgende parringer skal indhente RMCE-kompatibel KO blastocyster. For det første er heterozygote KO mus krydset med RMCE-kompatibel mus for at opnå RMCE-kompatibel, heterozygote KO mus. Disse mus anvendes derefter til timede parringer med andre heterozygote KO mus for at opnå 3,5-dpc, RMCE-kompatibel, homozygote KO blastocyster. Muligheden for at opnå en sådan embryo...

Watch this Scientific Journal Video about Structure-function Studies in Mouse Embryonic Stem Cells Using Recombinase-mediated Cassette Exchange at JoVE.com

Structure-function Studies in Mouse Embryonic Stem Cells Using Recombinase-mediated Cassette Exchange

Proteiner indeholder ofte flere domæner, som kan øve forskellige cellulære funktioner. Gene knock-outs (KO) anser ikke denne funktionel diversitet. Her rapporterer vi en rekombinationsmedieret kassette udveksling (RMCE) -baseret struktur-funktion tilgang i KO embryonale stamceller, som giver mulighed for den molekylære dissektion af forskellige funktionelle domæner eller varianter af et protein.

Struktur og funktion Studier i embryonale stamceller fra mus Brug rekombinase-medieret Cassette Exchange

Gene engineering in mouse embryos or embryonic stem cells (mESCs) allows for the study of the function of a given protein. Proteins are the workhorses of ...

The overall goal of this structure-function method is to dissect at the molecular level the role of different protein domains, or disease-relevance mutations, in naive or differentiated mouse embryonic stem cells. This method can help to reveal how different residues or domains of a protein can contribute to its function in a given cellular context. The main advantage of this technique is that it allows very efficient targeting of rescue constructs to the genome of knock out embryonic stem cells, or ES cells, and the investigation of their role in different cell types.To achieve this, we combine three highly efficient technologies. These include improved mouse embryonic stem cell isolation, recombination-based targeting factor assembly, and ES cell targeting via recombination-mediated cassette exchange, or RMC. Demonstrating some of the procedures will be Jinke D'Hont, a technician from my laboratory.Recombination-mediated cassette exchange, or RMCE, allows the interchange of DNA fragments between a vector and a genomic locus. RMCE takes advantage of hetero-specific recombination sites that do not cross-react and that are embedded in a genomic locus. In the presence of a donor plasmid that contains a DNA fragment flanked by the same hetero-specific sites, the recombinase will insert this DNA fragment into the RMCE-compatible genomic locus because of double simultaneous translocation.Only upon correct recombination, the trapped promoterless Neomycin-resistance gene in the Rosa 26 docking site, will be restored via a PGK promoter in the incoming targeting vector, which renders drug-resistance. This Neomycin resistance trap system results in a very high targeting efficiency, often close to 100%The day before blastocyst isolation, add 0.1%gelatin, to 12 well-cultured plates. And incubate them at 37 degrees Celsius for five minutes.Aspirate the gelatin solution. Then seed one quarter of a vial of P2 Mouse Embryonic Fibroblasts, or MEFs, into MEF medium, and divide over the 12-well plate. Incubate the 12-well plates of MEFs in two milliliters of MEF medium at 37 degrees Celsius.And grow the cells to a confluent monolayer. Then add 10 micrograms per milliliter of Mitomycin seed to the wells. And incubate the cultures for three hours at 37 degrees Celsius, to inactivate the cells.After selecting heterozygous knock out mice containing an RMCE cassette in the Rosa 26 locus according to the text protocol, set up matings to breed RMCE-compatible heterozygous knock out mice, with heterozygous knock out mice. The following morning, check for copulation plugs by lifting the female by the base of the tale, and examine the vaginal opening for a whitish mass. If the plug is difficult to see, with an angled probe, slightly spread the lips of the vulva, then separate the plugged females from their males.To collect blastocysts at 3.5 days post-coitus, or DPC. After euthanizing the pregnant females, make a mid-ventral incision, and use fine scissors and forceps to dissect the uterus and oviduct. Next, bend a 26-gauge needle into a 45-degree angle attached to a 1 milliliter syringe filled with M2 medium.And insert the needle into the end of the uterus that is closest to the oviduct. Use fine forceps to hold the needle in place while pushing the plunger to flush the blastocysts from the uterus into the lid of a 10 centimeter dish. The uterus will swell, if the flushing is successful.Use a mouth pipette to collect all the embryos in a drop of M2 medium, and wash the embryos twice in a drop of M2 medium. Immediately after washing the embryos, use PBS, to wash the mitomycin-C inactivated cells twice. Then using a mouth pipette, plate each blastocyst onto a separate well of the mitomycin-C treated MEFs, in SRES cell medium, supplemented with pluripotent or 2I.Incubate the cultures at 37 degrees Celsius, and 5%carbon dioxide. Refresh the SREF cell medium every two to three days. Examine each blastocyst under a stereo microscope at 4X magnification, and check for hatching and detachment to the MEF layer.After 10 to 12 days of culture, under a stereo microscope, use a P10 pipette with disposable tips, to pick individual icium outgrowths. Transfer each outgrowth into approximately 10 microliters of medium to a V-shaped 96-well plate, containing 30 microliters per well of PBS. Using a multi-channel pipette, add 50 microliters of 0.25%trypsin to each well.And incubate the plate at 37 degrees Celsius and 5%carbon dioxide for three minutes. Add 100 microliters of pre-incubated FPS-containing ES cell medium, and dissociate the icium outgrowths into single cells by pipetting 10 to 15 times. Then transfer the dissociated cells to mitomycin-C treated 96 well MEF plates.The following day, change the SR-based medium. Expand the ES cells in a similar fashion from 24 to 6-well plates. After identifying rescued CDNA vectors according to the text protocol, prepare a 10 microliter LR reaction using 100 nanograms of rescue CDNA vector, 150 nanograms of pre-excised RMCEDV1 vector, and two microliters of recombinase mix, containing a phage-encoded integrase, an excisionase, and a bacterial integration host factor.Incubate the reaction at 25 degrees Celsius for two hours. To transform the recombined vectors, add 5 microliters of each mixture, to 40 microliters of heat shock competent E.Coli bacteria, in a 2 milliliter skirted screw cap tube. And incubate the sample on ice for 20 minutes.Then incubate the cells at 37 degrees Celsius for five minutes. Add one milliliter of LB medium to the tube, and incubate the cells at 37 degrees Celsius for one hour. Plate 50 microliters on agar plates with ampicillin.And grow at 37 degrees Celsius overnight. Identify colonies with the correct targeting vector by using a P200 tip to randomly pick five colonies. Transfer the tip to a glass test tube containing two to five milliliters of LB medium, and grow overnight at 37 degrees Celsius.After extracting the DNA from each colony, validate the samples by digesting 0.5 to two micrograms of DNA, and separate the samples on a 1%agarose gel. Start a culture of RMCE compatible knock out ES cells, and passage them at least twice on MEFs, in FBS-based ES cell medium. Then split the ES cells on a gelatinized six-well plate.The following day, use 1.5 milliliters of FBS-based ES cell medium to refresh the ES cells that are about 50%confluent. Combine one microgram of pre-excised RMCEDV1 targeting vector, containing rescue CDNA, and one microgram of FLIPe expression plasmid, in 250 microliters of pure DMEM medium. Add seven microliters of lipofectin-based transvection reagent to 250 microliters of pure DMEM medium.And incubate the solution for five minutes at room temperature. Combine the DNA and lipofectin solutions. And incubate the mixture at room temperature for 20 minutes.Then pipette the transvection mixture onto the refreshed ES cells, and gently swirl. One day after transvection, split all ES cells from the tube to a 10-centimeter culture dish, with a confluent layer of DR4 MEFS, and 10 milliliters of FPS-based ES cell medium. Two days after transvection, select ES cell clones with the correct FLIP-e mediated cassette exchange, by adding G418 to the medium.As shown here, massive killing of non-targeted colonies should be visible after three to five days. Colonies should appear after seven to 10 days. Pick these colonies, then expand them, and verify the clones as demonstrated earlier in this video.To differentiate ES cells into embryoid bodies, or EBs, after culturing knock out ES cells with Rosa 26-driven rescue constructs according to the text protocol, allow EBs to form in the non-adherent dishes for 30 days. Refresh the medium every two to three days by transferring the EB suspension to a 50 milliliter tube. And let the EBs settle by gravity.Remove the supernatant, add fresh medium, and transfer the EB suspension to a bacterial-grade dish. Analyze the ES cells and EBs by immunofluorescence and TEM, according to the text protocol. Using the structure function method, five pre-excised RMCEDV1 targeting vectors were generated with an efficiency of 100%and these rescue constructs were targeted via RMCE, to P120 catenin knock out ES cells, with an efficiency of 97%Cystic EB morphology can be used as a phenotypic readout to screen different rescue constructs.As proof of concept, R26-driven P120 catenin isoform 1A rescued the p120 catenin knock out phenotype. To test whether E-cadherin independent membrane anchoring of P120 catenin enabled csytic EB formation, the k-ras membrane targeting motif, CAAX, was fused to the carboxy terminus of P120 catenin, and introduced via RMCE, to P120 catenin knock out ES cells, before EBs were made from them. However, this construct serves a dominant negative that does not allow binding and stabilization of E-cadherin.And as a consequence, does not rescue the p120 catenin knock out phenotype. Epithelial-mesenchymal transition, or EMT, is an essential developmental process that also occurs during ES cell differentiation. When expressed in p120 catenin knock out ES cells, the EMT inducers, ZEB1, ZEB2, or snail that can directly repress various epithelial marker genes like E-cadherin, failed to restore cystic EB formation.Once mastered, RMCE compatible ES cells can be isolated within one month. RMCE compatible targeting vectors can be generated within one week, and targeted rescue of ES cells can be achieved within one month using this technique, if it is performed properly. After watching this video, you should have a good understanding of how to use RMCE to perform structure function studies in naive or differentiated embryonic stem cells.

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